Automatic circuit breaker



June 30, 1931. J. SACHS 1,812,846

AUTOMATIC C IRGUIT BREAKER Filed April 6. 1929 i Patented June ,30, 1931 ,JOSEPH SACHS, F WEST HARTFORD, CONNECTICUT AUTOMATIC CIRCUIT BREAKER Application led April 8, 1929. Serial No. 353,052.

This invention relates particularly to circuit breakers of the type disclosed in my C0- pending applications for automatic circuit breakers Ser. No. 271,819,-iled April 21, 1928,

5,. Ser. No. 283,060, filed June 5, 1928 and Ser.

No. 332,924, filed January 16, 1929. In 'a y circuit breaker ofthis type the electro-responsive means, which may be a. thermostatic yelement such as an electro-thermal bi-metallic strip, is so mounted as to be bodily movable in whole or in part with the movable conta member of the circuit breaker;

In bitch of the before mentioned applications, the construction is such that the electro-responsive device, as for instance the electro-thermal strip, serves in and of itself as a releasable latch, which normally holds the contact member in its closed circuit position and which normally serves as a means whereby the contact member may be operated by the actuator for ordinary switching purposes. The construction referred to has the advantage of great simplicity and is for this reason ordinarily preferable. However, for some classes of service it may be desirable to avoid the use of the electro-responsive element as a mechanical connector while retaining the advantage resulting from the mounting of the said element for bodily movemen The principal object of the present invention is to provide a construction of the type referred to having means mechanically operative entirely independently of the electroresponsive element for normally holding and operating the contact member, the said means, however, being so constructed and so related with the electro-responsive element as to be automatically released to permit movement of the contact member upon the actuation of the said element by reason of the attainment of abnormal current conditions, such as passage of excess current.

Other objects of the invention wij.; be apparent from t-he following specification and claims.

As concerns the broader phases of the invention there can be wide variation as to some of the details of construction, lparticu- 5" larly as concerns the details of the main body and of the movable contact member. I prefer and have shown in t-he drawings a construction which as to these details is similar to the construction shown'in my aforesaid co-pending application, Ser. N o. 283,060. It will be understood that the drawings are intended for illustrative purposes only and are not to be construed as. defining or limiting the scope of the invention, the claims forming a part of this'specification being relied upon for that purpose.

Of the drawings:

F ig. 1 is a front view of a circuit breaker embodying the invention, the enclosing cover being shown in section.

Fig. 2 is a side view of the parts shown in Fig. 1, the cover and the base being shown in section along theline 2 2 of Fig. 1.

Fig. 3 is a transverse sectional view taken looking upward along the line 3 3 of Fig. 2.

Fig. 4 is a vertical sectional view taken along the line 4-4 of Fig. 2.

Fig. 5 is a detailed perspective view of the electro-thermal strip.

Fig. 6 is a fragmentary vertical sectional view taken along the line 6-6 of Fig. 1 and showing the parts in the same relative positions as in Fig. 2.

Figs. 7 and 8 are vertical sectional views similar to Fig. 6, the several parts being in different relative positions and being more fully shown. j

Referring to the drawings, it will be observed that the main body of the circuit breaker unit comprises two spaced insulating side plates 1, 1 and metallic cross members 2 and 3 connected at their ends with the side plates by means of nuts 4, 4. The said body of the circuit breaker unit is connected with a base 5 by means of 'nuts or screws 6, 6 which extend through holes in the members 2 and 3 and hold them in contact with metal plates 7 and 8 carried by the base. The said metal plates 7 and 8 are provided with screws 7a and 8*l constituting wire connecting terminals.

I provide a contact member which is movably mounted with respect to the body, preferably being mounted for pivotal movement. As illustrated the contact member includes two side plates 9, 9 which are pivotally mount le rounding the studs 10, 10. The two side,

plates 9, 9 are held in proper spaced relationship by means of spacing rods 13, 13, which are connected with the side plates by means of screws 14, 14.

Suitable electric contacts are provided, there preferably being two stationary contacts carried by the body of the circuit break-` er and two movable contacts carried by the contact member and adapted to be engaged with and'disengagedfrom the respective stationary contacts. The details of the contacts may be widely varied but as illustrated the two stationary contacts 15, 15 are carried respectively by vthe two side plates 1,' l. Each ofthe contacts 15 is formed as a part of a at strip 15a bent as shown in Fig. 2l and having the contact face thereof located in a transverse plane. As shown most clearly in Figs. 2 and 3 each side plate 1 is provided with an opening 16, and the corresponding contact is located immediately adjacent the opening and at the inner side of the plate.` Each contact strip 15, is provided with an ear 17, in a vertical plane at the outer side of the plate and held in engagement therewith by means of abolt 18. The right hand contact 15 is electrically connected with the lower transverse member 2 .by means of a strap 19 held n'place at its upper end by a nut on the corresponding bolt 18 and atits low-er end by the corresponding nut 4. The left hand contact 15 is electrically connected with the upper transverse member 3 by means of a strap 20 held in place at its lower end by-` nut on the corresponding bolt 18 and at its upper end by the corresponding nut 4.

The movable electrical contacts are shown at 21, 21, these contacts projecting laterally4 from the side plates 9, 9 of the contact mem- 'ber and being adapted to engage the stationary contacts 15, 15 as shown in Fig. 2. Extending transversely between the two side plates 9, 9 is an insulatingfbar 22 and the twoJ contacts 21, 21 are extended inward as shown at 21", 21* through suitable apertures in the side plates so as to engage the bar22 at the y lower face thereof as shown in Figs. 3, 7 and 8. txThe said contacts 21, 21 are held in place by means of screws 23, 23 extending through the bar 22.

The details of construction and mounting the fixed and movable contacts are not herein claimed, being set forth and claimed in my copending applications for automatic circuit breakers, Serial No. 283,060 iled J une 5, 1928 and Serial No. 365,419 filed May 23, 1929.

The entire contact member is biased for movement in the counter-clockwise direction 1 position. The

ber is pivotally mounted as shown and de-` scribed, the actuator is preferably also pivotally movably mounted for movement about an axis parallel with the contact member axis.

.As shown the actuator is in the form. of a member 25 pivotally mounted on a rod 26 extending transversely between the side plates 1, 1. The member 25 is held against transverse movement by means of bushings 27, 27 on the rod 26.

The member or actuator 25 is provided with a projection 28 constituting a handle whereby it may be moved manually. The actuator lhas an arcuate slot 3() therethrough and a rod 31 carried by the side plates 1, 1 extends through the slot. of its engagement with the ends of the s lot serves asa means for limiting the' movement of the actuator. The actuator is biased toward its open-circuit position, thatis toward its lower position, by means of a coil spring 32 surrounding one of the bushings 27, 27 the spring having its ends connected respectively with the corresponding side plates 1 and with the actuator.

I provide an electro-responsively controlled toggle link means between the actuator and the contact member which connection is operative to enable the actuator to operate the contact member for ordinary switching purposes and which is automatically released in so far as its holding (function is concerned upon the attainment of abnormal current conditions in thel circuit, so as to permit the contact member to automatically move independently of the actuator to its open-circuit electro-responsively controlled means may be widely varied in construction but it nis essential-s that at. least a' The rod by reason lon portion of the said means be mounted for bodily movement with the contact member, or with the actuator, or with both.

I prefer and have shown as ar part of' .be deflected by reas-on ofthe heating action of excess current therein in accordance with the well known actibn of, such bi-metallic strips. The loi-metallic strip i's shown in the drawingfat 33, this strip being substantially U-shaped and'having the legs of the U connected respectively`with the movable conf strip 33 provides an electrical connection between the two movable contacts 21, 21, thus,

)vhen the movable and fixed contacts are in engagement, completing the circuit through the entire unit.

The electro-responsively controlled means also includes a mechanical connection between the actuator and the contact member, this mechanical connection ordinarily being in the form of toggle links, such as 36 and 37 The two links are pivotally connected together at 38 and are respectively pivotally connected with the actuator and the contact member at 39 and 40. As shown the link 37 is a single link and the link 36 is a double link, preferably formed of a single sheet of metal with the two parts connected by an integral transverse element 41. This e ement 41 normally engages the. link 37 to vlim/it relative movement as clearly shown ijn Fig. 6. Preferably, a spring 42 is provided which tends to move the two links 36 and 37 into operative aligned position as shown. For limiting movement of the link 36 in the counter-clockwise direction there is provided a in 43 extending transversely between the si e plates 9, 9 and engaging an extension 36* on the link.- d

Provisionv is made whereby the electrothermal strip, upon being heated, serves to change the relationship of the toggle links, so

as to break the toggle and permit the contact member to move to its o en circuit position entirely independently o the actuator 25. I donot narrowly limit myself as concerns the relationship between the electro-thermal strip and the toggle links, but I have shown a construction whereinthe pivot between the contact member and the corresponding toggle link 37 is bodily movable with respect to the said member and wherein the electro-thermal strip serves to relativel move the said pivot and to thereby change t e relationship of the links for" the urpose s et forth. As shown there is provi ed a strut 44 which is guided for endwise movement relative to the contact member. The thermal Vstrip 33 is curved so as to 'assume a loop form and it is directly connected with the strut 44 by riveting or otherwise. The other end of the strutl serves as the means whereby the corresponding toggle link 37 is pivotally connected with the contact member. As shown the. strut 44 is bifurcated at its end and the link 37 is pivoted directly to it. For holding the strut 44 in place and for guiding it so as to permit endwise movement thereof I provide a rod 45 which extends transversely betweeny thef two side plates 9, 9 and which is held against rotation with respect to the said side plates. As` illustrated the rod-45 is provided'with squared portions at its ends which it into similarl shaped holes in the side. plates. The roel7 45 is provided with a guide opening therein throughl which the said strut 44 extends.

. Figs. 2 and 6 show the circuit breaker with the severa-l parts in their closed circuit positions, the movable contacts 21., 21 being in `engagement with the fixed contacts 15, 15.

The circuit is thus established from the terminal 7a through the cross member 2 and the strap 19 to the right hand contacts 15 and 21. From the right hand contacts the circuit extends through the thermal strip 33 to the left hand contacts and thence through the strap 20 and cross member 3 to the terminal 8a. The contact member. is held in its closed-circuit position as shown by means of the actuator? 25 and the toggle links 36 and 37. As clearly shown in Fig. 6 the axis at 38 is above a line connecting the axes 39 and 40,- the links 36 and 37 being thus held in t ir operative positions by reason of the pre sure exerted by the springs 24, 24 tending to move the contact member in the counter-clockwise direction.

LAs also clearly shown in Fig. 6 the axis at 39 is below a line connecting the axes 26 and,40, the action of the combined links 36 and 37 therefore being to resist the tendency of the actuator to move in thecounterclockwise direction under the influence of the spring 32.

Notwithstanding, the tendency of toggle links to hold the actuator in its closed-circuit position as shown in Fig. 6 the said actuator can be easily moved manually to the position shown in Fig. 7 so as to permit the movement of the contact member in the counter-clockwise direction to its open-circuit position. In fact, by means of the toggle links the contact member can be easily moved by the han-(ef dle in either direction for ordinary switching pur oses.

pon the passage of excess current through' the electro-thermal strip 33 there is a tendency for the said strip to straighten out, thus,

moving the strut 44 upward as shown in Figs.

2 and 6, the said strut being guided as before stated in the transverse rod 45. Movement of the strut upward serves to move the pivot 40 upward and, inasmuch as the link 3 6 is held by reason of its engagement with the in 43, the operative relationship of said links 36 and 37 is broken and the contact member is free to move to its open-circuit po, sition under the influence of the4 s rings 24, 24. It will be understood that th ment to open-circuit position takes place entirely independently of the actuator and will occur even 1f the actuator is held in its closedis move# `circuit position. Fig. 8 shows the contact ever, the handle is released or if it is not held atall itimmediately moves to its open-circuit position. As soon as it reaches its open-circuit position the toggle links 36 and 37 again assume their normal operative relationship as shown in Fig. 7.' When the er unit, that is, the side plates 1, 1 and the parts carried thereby may be mounted upon a base 5 such as already described or may be` otherwise used, either separately or 1n combination with other electrical devices.l

When mounted upon a base such as 5 it may be enclosed in a sheet metal casing such as 46 having an opening through which the handle part of' the actuator projects. As illustrated the casing-46 is secured to the base 5 by means of screws 47, 47.

What I claim is: l v

1. An automatic circuit breaker comprising in combination, a movable contact member biased for movement towards its opencircuit position, a pair of toggle links adapted when intheir operative relationship to hold the contact member in its closed-circuit position, and an electro-'responsive means comprising any element inherently responsive to abnormal current conditions in the circuit, the said element'being bodily movable with the said contact member and serving uponv the passage of excess current through the electro-responsive means to change the relationship of the toggle links so asa to releasethe contact member and permit automatic moyement thereof to its open-circuit posi.- tion. l Y

2. An automatic circuit breaker as set forth in claim 1, wherein the pivot between the contact member and the corresponding tog le link is bodily movable with respect to t e said member and wherein the electroresponsive device serves to relatively move the said pivot and to thereby change the relationship of the linl for the purpose set forth.

3. An automatic circuit breaker comprising in combination, a movable contact member biased for movement toward its openc1rcu1t position, and an electro-responslvely controlled togglelink means normally serv- 'ing to hold the cont-act member in its closedcircuit position, the said means including a thermostatic element bodily movable with the said contact member and serving upon the attainment of abnormal current conditions in the circuit to change the toggle link relationship so as to release the contact member and permit automatic movement thereof to its open-circuit position.

' '4. A circuit breaker as set forth in claim i 3, wherein the thermostatic element is structurally separate from the toggle links, the

' ber biased for movement toward its open circuit position, a pair of toggle links of which one is connected with the contact member, the said links when in their operative relationship serving tohold the contact member in itsclosed circuit position, and a thermostatic element bodilymovable with the said contact member vand serving upon the passage of excess current through the circuit to bodily move the pivotal connection between the contact member and the corresponding toggle link so as to change the relationship of the links and thereby release theA contact member and permit automatic movement thereof to its open circuit position. f

6. .An automatic circuit breaker as set forth in claim 5, wherein the thermostatic element is a current carrying bi-metallic strip, and wherein there is a strut guided for endwise movement relatively to the contact member, the said strut being connected at one end with the bi-metallicstrip so as to be moved thereby and serving at the other end as the means whereby the corresponding toggle link is pivotally connected with the contact member.

7. An lautomatic circuit breaker comprising/in combination, a manually operable actuator, a contact member biased for movement lindependently ofthe actuator toward its open-circuit position, a pair of toggle links `pivotally connected respectively with the actuator and the contact member and serving when in their operative relationship toI transmit the motion of the actuator to move the contact `member for ordinary switching l purposes, and an electro-responsive means comprising an element inherently responsive to abnormal current conditions in the circuit, the said element being bodily movable with the said contact member and serving upon the passage ofexcess current to change the relationship of the toggle links so as to vrelease the contact member and permit automatic movement thereof to its open-circuit position independently of the actuator.

8. An automatic circuit breaker comprising in combination, a manually operable 'actuator biased for movement toward'its opencircuit position, a contact member biased for movement independently of thenactuator toward its open-circuit position, a pair of toggle p links pivotally connected respectively withy the actuator and the contact member and nor- 1 mally serving when in their operative relayio tionship to hold the contact member in its closed-circuit position and to transmit pressure from the contact member to lalso hold the actuator in its closed-circuit position, the said links also yserving upon manual movement ofthe actuator to move the contact member for ordinary switching purposes, and an electro-responsive device connected in the circuit and bodily movable with the sai-d contact member, the said device serving upon the passage of excess current to change the relationship of the toggle links so as to release both the actuator and the contact member and permit automatic movement thereof circuit positions.

.9. An automatic circuit breaker comprising in combination, a manually operable actuator, a contact member biased for movement independently of the actuator toward its open-circuit position, a pair of toggle links pivotally connected respectively with the actuator and the contact member and serving when in their operative relationship to transmit the motion of the actuator to move the contact member for ordinary switching purposes, and an electro-thermal strip connecte-d in the circuit with one portion thereof rigidly secured to the contact member and with another portion thereof electro-thermally movable, the said strip serving upon the passage of excess current to change the relationship of the toggle links so as to release-the contact member and permit automatic movement thereof to its open-circuit position independentlyvof the actuator. 10. An automatic circuit breaker comprising in combination, a contact member pivotally movable about a fixed axis and biased for movement toward its open-circuit position, a pair of toggle links adapted when in their operative relationship to hold the contact member inits closed-circuit position, and

an electro-responsive device connected in the circuit and bodily movablewith the said contact member, the said device serving upon the passage of excess current to change the relationship of the toggle links sofas to release the contact member and permit automatic pivotal movementQhereof to its open-circuit position. y

11. An automaticcircuit breaker comprising in combination, a manually operable actuator pivotally movable about a fixed axis and biased for movement towardslits opencircuit position,'a'contact member pivotally movable about a separate fixed axis,parallel lto the first said axis and biased for movement independently of the actuator toward links pivotally connected respectively with the actuator and the contact member andnormally serving when in their operative relationship to hold the contact member in its a5 closed-circuit position and to transmit preseach independently of the other to their openits open-circuit position, a pair of toggle sure from the contact member to also hold the actuator/in its closed-circuit position, the said links also serving upon manual movement of the actuator to move the contact member for ordinary switching purposes, and an electrothermal strip connected in the circuit and bodily movable 1with the said contact member, the said device serving upon the passage of excess current to change the relationship ofthe toggle links so as to release both the actuator and the contact member and permit automatic pivotal movement thereof each independently of the other to their open-circuit positions.

12. An automatic circuit breaker comprising in combination, a manually operable actuator pivotally movable yabout a fixed axis and biased for movement toward its vopencircuit position, a contact member pivotally movable about a fixed axis and .biased for 85 movement independently of th-e actuator toward its open-circuit position, a pair of toggle links pivotally connected respectively with 4the actuator and the contact member and serving when in their operative relationship to transmit the motion of the actuator to move the contact member for ordinary switching purposes, and an electro-thermal strip connected in the circuit with one portion thereof rigidly secured to the contact member and with another portion thereof electro-thermally movable, the said strip` serving upon thepassage of excess current to change the relationship of the toggle links so as to release the contact member and per- 100 mit automatic pivotal movement thereof to its open-circuit position independently of' the actuator.

y 13. A circuit-breaker as set forth in claim 12, wherein the pivot between the contact member and the corresponding toggle link is bodily movable with respect to the said member and wherein the electro-thermal strip serves torelatively move the said pivot and to thereby change the relationship of the links for the purpose set forth.

14. An automatic circuit breaker comprising in combination, la, manually operable actuator, a contact member pivotally movable about a fixed axis and comprising two par-115. allel side platesv spaced apart and perpendicu- -lar to the pivotal axis, two fixed electric con-` tactsat opposite sides of the said contact Imember, two electric contacts carried respectively by the side plates and movable intoy and out of engagement respectively with the fixed contacts, a pair of toggle links pivotally connected respectively with the actuator and with the contact memberbetween the side plates "thereof, the said links serving when in their operative relationship to transmit the motion of the actuator to move the Contact member for ordinary switching puroses, and an electro-thermal strip carried y the contact member between the side plates thereof and electrically connected between the two movable contacts, the said strip serving upon the passage of excess current to change the relationshipvo the toggle links so as to release the contact member and permit automatic pivotal movementthereof to its open-circuit position independently of the actuator. i

15. A circuit breaker as set forth in claim 10 14,' wherein there is a strut mounted! bef tween the contact member side plates for movement parallelly therewith, the said strut y beingl connected at one end with the electrothermal strip so as'to be moved thereby serv- 15 ing at the other end as the means whereby the corresponding toggle link lis pivotally connected with the contact member. f

In testimony whereof I have hereunto se my hand this 21st day of March, 1929. 20 JOSEPH SACHS.' 

